Estimation of Ground Reaction Forces during Sports Movements by Sensor Fusion from Inertial Measurement Units with 3D Forward Dynamics Model.

Rotational jumps are crucial techniques in sports competitions. Estimating ground reaction forces (GRFs), a constituting component of jumps, through a biomechanical model-based approach allows for analysis, even in environments where force plates or machine learning training data would be impossible. In this study, rotational jump movements involving twists on land were measured using inertial measurement units (IMUs), and GRFs and body loads were estimated using a 3D forward dynamics model. Our forward dynamics and optimization calculation-based estimation method generated and optimized body movements using cost functions defined by motion measurements and internal body loads. To reduce the influence of dynamic acceleration in the optimization calculation, we estimated the 3D orientation using sensor fusion, comprising acceleration and angular velocity data from IMUs and an extended Kalman filter. As a result, by generating cost function-based movements, we could calculate biomechanically valid GRFs while following the measured movements, even if not all joints were covered by IMUs. The estimation approach we developed in this study allows for measurement condition- or training data-independent 3D motion analysis.

Multibody Model with Foot-Deformation Approach for Estimating Ground Reaction Forces and Moments and Joint Torques during Level Walking through Optical Motion Capture without Optimization Techniques.

The biomechanical-model-based approach with a contact model offers advantages in estimating ground reaction forces (GRFs) and ground reaction moments (GRMs), as it does not rely on the need for training data and gait assumptions. However, this approach faces the challenge of long computational times due to the inclusion of optimization processes. To address this challenge, the present study developed a new optical motion capture (OMC)-based method to estimate GRFs, GRMs, and joint torques without prolonged computational times. The proposed approach performs the estimation process by distributing external forces, as determined by a multibody model, between the left and right feet based on foot deformations, thereby predicting the GRFs and GRMs without relying on optimization techniques. In this study, prediction accuracies during level walking were confirmed by comparing a general analysis using a force plate with the estimation results. The comparison revealed excellent or strong correlations between the prediction and the measurements for all GRFs, GRMs, and lower-limb-joint torques. The proposed method, which provides practical estimation with low computational cost, facilitates efficient biomechanical analysis and rapid feedback of analysis results, contributing to its increased applicability in clinical settings.

Cobalt-Catalyzed Divergent Cycloadditions of Alkynes with Conjugated Dienes Yielding 3-Vinylcyclobutenes, Bicyclo[3.1.0]hexenes, and Cyclohexa-1,4-dienes.

A traditional cobalt catalyst system still contains undiscovered reactivity. Depending on the tertiary phosphines and substrates used, the catalytic system using CoBr2/tertiary phosphine/Zn/ZnI2 catalyzes divergent cycloadditions of internal alkynes with conjugated dienes, yielding 3-alkenylcyclobut-1-enes, bicyclo[3.1.0]hexenes, and cyclohexa-1,4-dienes. A [CoBr2(PPh3)2]/Zn/ZnI2-catalyzed reaction of 3-hexyne (1a) with 1-(4-methoxyphenyl)butadiene (2a) at room temperature in CH2Cl2 exclusively produces a [2 + 2] cycloaddition product (E)-2-(2,3-diethylcyclobut-2-ene-1-yl)vinyl-4-methoxybenzene (3aa). When [CoBr2(dppp)]/Zn/ZnI2 is used as a catalyst, a bicyclic compound 6-(4-methoxyphenyl)-2,3-diethylbicyclo[3.1.0]hex-2-ene (4aa) is dominantly formed in a 77% yield. The CoBr2/dppe/Zn/ZnI2 system can undergo a [2 + 4] cycloaddition to yield 3-(4-anisyl)-1,2-diethylcyclohexa-1,4-diene (5aa) as the dominant product in 38% yield. The bite angles of the ligands used contribute significantly to this catalytic diversity.

Investigation of the relationship between steps required to stop and propulsive force using simple walking models.

To prevent falls in the elderly, it is essential to evaluate their gait stability and identify factors that negatively affect it. Although one of the probable factors is a decrease in propulsive force of walking, the relationship between the force and the gait stability has not been fully clarified. To this end, two simple walking models were used to investigate the relationship between the propulsive force and the number of steps required to stop, denoted N. N was calculated as the number of steps required for the rimless wheel to stop and was treated as a variable which is an indirect indicator of stability. A lower N corresponds to the gait being closer to a stopped state. The propulsive force was calculated using the push-off impulse applied to the simplest walking model during the step-to-step transition. To account for the effects of the double support phase in human walking, the gravitational impulse, which is the integral of the body weight (gravitational force) over the double support time, was applied to the step-to-step transition equation of the models. The models revealed that the propulsive force is reduced by two factors: the reduction in step length and the reduction in walking speed. In the former, N increases; in the latter, N decreases. The former is consistent with previous experimental results on human gait, whereas the latter has not been experimentally investigated. These results may provide important insights in clarifying the relationship between the stability and the propulsive force in human gait.

Clinical significance of primary tumor score determined by tumor depth and size in patients with resectable gastric cancer.

Although postoperative management of gastric cancer is determined by pathological stage based on the tumor-node-metastasis classification, predicting disease recurrence and prognosis in patients undergoing gastrectomy is clinically difficult. We investigated the depth of tumor invasion and tumor size in resected specimens from patients with gastric cancer and assessed the clinical utility of primary tumor score (PTS) calculated by tumor depth and size as a prognostic marker. We classified 247 patients with gastric cancer into three groups based on cut-off values for deeper tumor invasion (pT2-T4) and larger tumor size (≥ 45 mm) as a PTS of 2 (both abnormalities), 1 (one abnormality), or 0 (neither abnormality). PTS correlated significantly with lymph node metastasis, lymphovascular invasion, and stage (P < 0.0001 each). Survival differences among groups based on PTS were significant (P < 0.0001). Multivariate analysis identified PTS alone as an independent prognostic factor (P = 0.0363). PTS derived from primary tumor information alone is a potentially useful marker for predicting tumor progression and prognosis in postoperative patients with gastric cancer.

Clinical application and outcomes of sentinel node navigation surgery in patients with early gastric cancer.

Sentinel node navigation surgery (SNNS) has been recognized as a minimally invasive tool for individualized lymphadenectomy in patients with early gastric cancer (EGC). The aim of this study was to compare clinicopathological factors, adverse events, and clinical outcomes between sentinel node mapping (SNM) and SN dissection (SND) groups and assess the clinical utility of SNNS in patients with EGC. The clinical data of 157 patients with EGC, diagnosed as clinical T1N0M0 with tumors ≤ 40 mm, undergoing SNNS between March 2004 and April 2016 were retrospectively reviewed. Twenty-seven patients were excluded from the analysis. In the remaining 130 patients, 59 and 71 patients underwent standard lymphadenectomy for SNM and SND, respectively. The sentinel node detection rate in the SNM and SND groups was 98.3% (58/59) and 100% (71/71), respectively. Two (3.5%), 15 (25.9%), and 41 (70.7%) patients having sentinel nodes underwent total gastrectomy, proximal gastrectomy (PG), and distal gastrectomy (DG), respectively, in the SNM group. One (1.4%), 5 (7.0%), 10 (14.1%), 39 (54.9%), and 16 (22.5%) patients underwent PG, DG, segmental gastrectomy, local resection, and endoscopic submucosal dissection, respectively, in the SND group. There was no significant difference in postoperative complications between the SNM and SND groups (P = 0.781). Survival did not differ between the both groups (P = 0.856). The present results suggest that personalized surgery with SND provides technical safety and curability related with a favorable survival outcome in patients with EGC.

Sentinel node navigation surgery for gastroduodenal neuroendocrine tumors: Two case reports.

The percentage of gastroduodenal neuroendocrine tumors (NETs) among all gastroenteropancreatic (GEP) NETs has gradually increased worldwide. Sentinel node navigation surgery (SNNS) has been developed as a personalized approach in the surgical strategy for early gastrointestinal tract cancers. We herein report 2 cases of gastroduodenal NETs treated with SNNS. Technetium-tin colloid including indocyanine green was endoscopically injected into the submucosa around a tumor the day before surgery. Basin dissection including the sentinel nodes (SNs), which were identified by Navigator GPS and near-infrared fluorescence imaging, was performed during laparoscopic surgery. SNs were intraoperatively examined using hematoxylin-eosin (HE) staining.SNs were detected in 2 patients. Lymph node metastasis was intraoperatively identified in 1 of the 2 patients. Consequently, 1 patient with metastatic SNs underwent laparoscopic gastrectomy with lymphadenectomy. Pathological findings identified submucosal NET measuring 6.0 mm × 5.0 mm.Our results suggest that SNNS is a promising surgical tool for detecting subclinical lymph node metastasis in patients with gastroduodenal NETs.

The clinical usefulness of the intraoperative detection of sentinel lymph node metastases by a rapid RT-PCR system in patients with gastric cancer.

BACKGROUND: The incidence of pathological lymph node metastases in patients with gastric cancer is 5% to 10%, which means that approximately 90% of patients with gastric cancer may undergo unnecessary lymphadenectomy. The precise intraoperative diagnosis of sentinel lymph node (SN) metastases is essential. The purpose of the current study was to verify the usefulness of a rapid reverse transcriptase-polymerase chain reaction (RT-PCR) system compared with hematoxylin and eosin staining for such diagnoses. METHODS: A total of 113 patients with clinical T1-T2 (cT1-T2) gastric cancer, including 73 patients with cT1cN0 disease with a tumor diameter <4 cm, were enrolled in the current study. SNs were identified by a radioisotope method. Carcinoembryonic antigen and cytokeratin 19 were used as markers for RT-PCR and the cutoff values were set using 1701 lymph nodes harvested from 157 patients with gastric cancer. RESULTS: SNs were detected in all 113 patients. Sensitivity and accuracy for detection by paraffin section were both 100% in patients with cT1 disease and were 60% and 90%, respectively, in patients with cT2 disease. The sensitivity of RT-PCR for the detection of pathological SN metastases was 92.3%. Furthermore, 11 patients had SN metastases detected only by RT-PCR, and these patients had frequent lymphatic invasion. Hematoxylin and eosin staining detected SN metastases in 6 of 73 patients with cT1cN0 gastric cancer; RT-PCR and frozen section detected SN metastases in 6 and 4 of these patients, respectively. Accordingly, the sensitivity of RT-PCR and frozen section for the detection of those pathological SN metastases were 100% and 66.6%, respectively. CONCLUSIONS: The rapid RT-PCR system appears to have clinical usefulness for the intraoperative detection of SN metastases in patients with gastric cancer.

Clinical Significance of Circulating Tumor Cells in Peripheral Blood of Patients with Esophageal Squamous Cell Carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma is an aggressive gastrointestinal tract cancer. To date, the presence of circulating tumor cells (CTC) has been reported as a prognostic factor in peripheral blood from patients with gastrointestinal cancers. METHODS: The CellSearch system was used to isolate and enumerate CTCs. A total of 90 patients with esophageal squamous cell carcinoma who received chemotherapy or chemoradiotherapy were enrolled. Peripheral blood specimens were collected before and after treatments. RESULTS: At baseline analysis, CTCs were detected in 25 patients (27.8 %). Overall survival was significantly shorter in patients with than without CTCs. Follow-up blood specimens were obtained from 71 patients. Partial response, stable disease, and progressive disease after treatment were seen in 32, 12, and 27 patients, respectively. CTC positivity after treatment in the progressive disease group (40.7 %) was significantly higher than that of the partial response group (6.3 %). Patients with a change in CTC status from positive to negative had a good prognosis as well as patients without baseline CTCs. CONCLUSIONS: Evaluation of CTCs may be a promising indicator for predicting tumor prognosis and the clinical efficacy of chemotherapy or chemoradiation therapy in patients with esophageal squamous cell carcinoma.

Clinical significance of stanniocalcin 2 expression as a predictor of tumor progression in gastric cancer.

Stanniocalcin 2 (STC2) is a glycoprotein hormone that plays an important role in calcium and phosphate homeostasis. Furthermore, recent studies have demonstrated that STC2 expression in the primary site is correlated with tumor progression in several types of malignancies. However, few reports have investigated the clinical significance of STC2 expression in the blood of patients with gastric cancer. Therefore, we examined STC2 expression as a molecular blood marker for detection of circulating tumor cells (CTCs) and assessed the relationship between STC2 expression and clinico-pathological features including prognosis in patients with gastric cancer. Quantitative PCR assay was used to assess STC2 mRNA expression in 4 gastric cancer cell lines and in blood specimens from 93 patients with gastric cancer and 22 healthy volunteers. The numbers of STC2 mRNA copies were significantly higher in the gastric cancer cell lines and in blood from patients with gastric cancer than in blood from healthy volunteers (P=0.0002 and P=0.01, respectively). STC2 expression was positive in 43 (46.2%) of the 93 patients with gastric cancer, and its expression was significantly correlated with age, depth of tumor invasion, lymph node metastasis, stage and venous invasion (P=0.023, P=0.045, P=0.035, P=0.007 and P=0.027, respectively). The 5-year survival rate was significantly lower in patients with STC2 expression compared to patients without STC2 expression (P=0.014). Our results indicate that STC2 could be a useful molecular blood marker for predicting tumor progression by monitoring CTCs in patients with gastric cancer.

Clinical significance of circulating tumor cells in peripheral blood from patients with gastric cancer.

BACKGROUND: The authors hypothesized that circulating tumor cells (CTCs) in patients with gastric cancer are associated with prognosis and disease recurrence. In this study, they evaluated CTCs in gastric cancer and clarified the clinical impact of CTCs. METHODS: In total, 265 consecutive patients with gastric cancer were enrolled. Fourteen patients were excluded from the analysis, including 12 patients who another cancer and 2 patients who refused the treatment. The remaining 251 patients were divided into 2 groups: 148 patients who underwent gastrectomy (the resection group) and 103 patients who did not undergo gastrectomy (the nonresectable group). Peripheral blood samples were collected before gastrectomy or chemotherapy. A proprietary test for capturing, identifying, and counting CTCs in blood was used for the isolation and enumeration of CTCs. RESULTS: CTCs were detected in 16 patients (10.8%) from the resection group and in 62 patients (60.2%) from the nonresectable group. The overall survival rate for the entire cohort was significantly lower in patients with CTCs than in those without CTCs (P < .0001). In the resection group, relapse-free and overall survival in patients with CTCs was significantly lower than in patients without CTCs (P < .0001). It was noteworthy that the expression of CTCs was an independent factor for determining the overall survival of patients with gastric cancer in multivariate analysis (P = .024). In the nonresectable group, the overall survival rate was significantly lower in patients with CTCs than in those without CTCs (P = .0044). CONCLUSIONS: The evaluation of CTCs in peripheral blood may be a useful tool for predicting tumor progression, prognosis, and the effect of chemotherapy in patients with gastric cancer.

Expression of stanniocalcin 1 as a potential biomarker of gastric cancer.

OBJECTIVE: We investigated stanniocalcin 1 (STC 1) expression to assess its clinical utility as a blood marker in patients with gastric cancer and evaluated its biological impact in terms of tumor aggressiveness. METHODS: Blood specimens from 93 patients with gastric cancer and 21 normal healthy volunteers were assessed by quantitative reverse transcription-polymerase chain reaction for STC 1 mRNA expression. RESULTS: The relative numbers of STC 1 mRNA copies were significantly higher in gastric cancer cell lines and in blood specimens from patients with gastric cancer than in blood specimens from healthy volunteers (p = 0.0001 and p = 0.003, respectively). The sensitivity and specificity of STC 1 mRNA expression for discriminating patients with gastric cancer from healthy volunteers were 69.9 and 71.4%, respectively. Furthermore, the sensitivity for STC 1 mRNA was higher than that for serum carcinoembryonic antigen and carbohydrate antigen 19-9. The presence of STC 1 expression was significantly correlated with depth of tumor invasion and tumor stage (p = 0.032 and p = 0.013, respectively). CONCLUSION: Our data strongly suggest that STC 1 is a potentially useful blood marker for predicting biological tumor aggressiveness in patients with gastric cancer.

Clinical significance of the B7-H4 coregulatory molecule as a novel prognostic marker in gastric cancer.

BACKGROUND: The B7-H4 coregulatory molecule is a member of the B7 family of molecules, which regulate the T-cell-mediated immune response through CD28 receptors. Recently, B7-H4 has been reported to be a negative regulator of the immune response in patients with several malignant diseases. However, few reports have investigated the clinical significance of B7-H4 expression in patients with gastric cancer. In the present study, we analyzed B7-H4 expression and the relationship between its expression and clinicopathological factors including prognosis in gastric cancer. METHODS: B7-H4 expression in gastric cancer cell lines and clinical gastric cancer specimens was initially assessed with the reverse transcription-polymerase chain reaction (RT-PCR). Moreover, B7-H4 and CD3 expression in 120 resected specimens from gastric cancer patients were evaluated by immunohistochemistry (IHC). RESULTS: B7-H4 expression was identified in the gastric cancer cell lines and clinical tumor tissues by RT-PCR. B7-H4 expression was high in 25.8% (31/120) of resected tumor specimens. B7-H4 expression significantly correlated with tumor stage (P = 0.04). The 5-year survival rate was significantly lower in patients with high B7-H4 expression than in those with low B7-H4 expression (P = 0.001). Multivariate analysis demonstrated that B7-H4 expression was an independent prognostic factor (P = 0.035). Immunohistochemical analysis of CD3 expression showed that B7-H4 expression was inversely correlated with the number of tumor infiltrating T lymphocytes (P < 0.001). CONCLUSIONS: The B7-H4 coregulatory molecule is a novel prognostic marker related to the T-cell-mediated immune response, and its pathway may be a molecular target for controlling tumor progression in patients with gastric cancer.